/* libunwind - a platform-independent unwind library Copyright (C) 2010, 2011 by FERMI NATIONAL ACCELERATOR LABORATORY Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ #ifdef HAVE_CONFIG_H # include "config.h" #endif #include #if HAVE_EXECINFO_H # include #else extern int backtrace (void **, int); #endif #include #include #include #include #include #include #define panic(args...) \ { fprintf (stderr, args); exit (-1); } #ifndef HAVE_SIGHANDLER_T typedef RETSIGTYPE (*sighandler_t) (int); #endif #define SIG_STACK_SIZE 0x100000 int verbose; int num_errors; /* These variables are global because they * cause the signal stack to overflow */ char buf[512], name[256]; void *addresses[3][128]; unw_cursor_t cursor; ucontext_t uc; static void do_backtrace (void) { unw_word_t ip; int ret = -UNW_ENOINFO; int depth = 0; int i, n, m; if (verbose) printf ("\tnormal trace:\n"); unw_getcontext (&uc); if (unw_init_local (&cursor, &uc) < 0) panic ("unw_init_local failed!\n"); do { unw_get_reg (&cursor, UNW_REG_IP, &ip); addresses[0][depth] = (void *) ip; } while ((ret = unw_step (&cursor)) > 0 && ++depth < 128); if (ret < 0) { unw_get_reg (&cursor, UNW_REG_IP, &ip); printf ("FAILURE: unw_step() returned %d for ip=%lx\n", ret, (long) ip); ++num_errors; } if (verbose) for (i = 0; i < depth; ++i) printf ("\t #%-3d ip=%p\n", i, addresses[0][i]); if (verbose) printf ("\n\tvia backtrace():\n"); n = backtrace (addresses[1], 128); if (verbose) for (i = 0; i < n; ++i) printf ("\t #%-3d ip=%p\n", i, addresses[1][i]); if (verbose) printf ("\n\tvia unw_backtrace():\n"); m = unw_backtrace (addresses[2], 128); if (verbose) for (i = 0; i < m; ++i) printf ("\t #%-3d ip=%p\n", i, addresses[2][i]); if (m != depth+1) { printf ("FAILURE: unw_step() loop and unw_backtrace() depths differ: %d vs. %d\n", depth, m); ++num_errors; } if (n != depth+1) { printf ("FAILURE: unw_step() loop and backtrace() depths differ: %d vs. %d\n", depth, n); ++num_errors; } if (n == m) for (i = 1; i < n; ++i) /* Allow one in difference in comparison, trace returns adjusted addresses. */ if (labs((unw_word_t) addresses[1][i] - (unw_word_t) addresses[2][i]) > 1) { printf ("FAILURE: backtrace() and unw_backtrace() addresses differ at %d: %p vs. %p\n", i, addresses[1][n], addresses[2][n]); ++num_errors; } if (n == depth+1) for (i = 1; i < depth; ++i) /* Allow one in difference in comparison, trace returns adjusted addresses. */ if (labs((unw_word_t) addresses[0][i] - (unw_word_t) addresses[1][i]) > 1) { printf ("FAILURE: unw_step() loop and backtrace() addresses differ at %d: %p vs. %p\n", i, addresses[0][n], addresses[1][n]); ++num_errors; } } void foo (long val) { do_backtrace (); } void bar (long v) { extern long f (long); int arr[v]; /* This is a vain attempt to use up lots of registers to force the frame-chain info to be saved on the memory stack on ia64. It happens to work with gcc v3.3.4 and gcc v3.4.1 but perhaps not with any other compiler. */ foo (f (arr[0]) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + f (v)) )))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))) ))))))))))))))))))))))))))))))))))))))))))))))))))))))); } void sighandler (int signal, void *siginfo, void *context) { ucontext_t *uc = context; int sp; if (verbose) { printf ("sighandler: got signal %d, sp=%p", signal, &sp); #if UNW_TARGET_IA64 # if defined(__linux__) printf (" @ %lx", uc->uc_mcontext.sc_ip); # else { uint16_t reason; uint64_t ip; __uc_get_reason (uc, &reason); __uc_get_ip (uc, &ip); printf (" @ %lx (reason=%d)", ip, reason); } # endif #elif UNW_TARGET_X86 #if defined __linux__ printf (" @ %lx", (unsigned long) uc->uc_mcontext.gregs[REG_EIP]); #elif defined __FreeBSD__ printf (" @ %lx", (unsigned long) uc->uc_mcontext.mc_eip); #endif #elif UNW_TARGET_X86_64 #if defined __linux__ printf (" @ %lx", (unsigned long) uc->uc_mcontext.gregs[REG_RIP]); #elif defined __FreeBSD__ printf (" @ %lx", (unsigned long) uc->uc_mcontext.mc_rip); #endif #endif printf ("\n"); } do_backtrace(); } int main (int argc, char **argv) { struct sigaction act; stack_t stk; verbose = (argc > 1); if (verbose) printf ("Normal backtrace:\n"); bar (1); memset (&act, 0, sizeof (act)); act.sa_handler = (void (*)(int)) sighandler; act.sa_flags = SA_SIGINFO; if (sigaction (SIGTERM, &act, NULL) < 0) panic ("sigaction: %s\n", strerror (errno)); if (verbose) printf ("\nBacktrace across signal handler:\n"); kill (getpid (), SIGTERM); if (verbose) printf ("\nBacktrace across signal handler on alternate stack:\n"); stk.ss_sp = malloc (SIG_STACK_SIZE); if (!stk.ss_sp) panic ("failed to allocate %u bytes\n", SIG_STACK_SIZE); stk.ss_size = SIG_STACK_SIZE; stk.ss_flags = 0; if (sigaltstack (&stk, NULL) < 0) panic ("sigaltstack: %s\n", strerror (errno)); memset (&act, 0, sizeof (act)); act.sa_handler = (void (*)(int)) sighandler; act.sa_flags = SA_ONSTACK | SA_SIGINFO; if (sigaction (SIGTERM, &act, NULL) < 0) panic ("sigaction: %s\n", strerror (errno)); kill (getpid (), SIGTERM); if (num_errors > 0) { fprintf (stderr, "FAILURE: detected %d errors\n", num_errors); exit (-1); } if (verbose) printf ("SUCCESS.\n"); return 0; }